CLIAMS:We claim:
1. A speed governing system to limit speed of a vehicle to a limiting speed value, the speed governing system comprising:
a speed governor, wherein the speed governor comprises:
one or more input channels;
a processor configured to:
receive one or more independent acceleration request from one or more input channels;
compare instant speed of the vehicle with at least one of nearest threshold limit value and limiting speed value;
compare the independent acceleration with a set limit corresponding to the nearest threshold limit value;
independently modify the one or more independent acceleration request received from one or more input channels based on at least one of the comparisons.
2. A speed governing system according to claim 1, wherein the one or more independent acceleration request is modified if the instant speed of the vehicle is greater than the limiting speed value.
3. A speed governing system according to claim 1, wherein the one or more independent acceleration request is modified if the instant speed is greater than nearest threshold limit value, and the requested rate of acceleration is greater than the set limit corresponding to the nearest threshold limit value.
4. A speed governing system according to claim 1, wherein the speed governor includes a plurality of threshold limit values and set limit values.
5. The speed governing system according to claim 1, further comprising an electronic throttle pedal, wherein the electronic throttle pedal comprises
one or more channel and a throttle pedal in the vehicle, wherein, each of the channels are configured to sense the acceleration request from a throttle pedal in the vehicle, with each of the channels having its own characteristics, supply and ground connection.
6. The speed governing system according to claim 1, further comprising a vehicle control unit configured to modify the operation of different parts of the vehicle based on the acceleration request received from the speed governor.
7. The speed governing system according to claim 1, wherein each of the input channels are independently governed by the speed governor.
8. The speed governing system according to claim 1, wherein the speed governor further comprises a memory unit configured to store information corresponding to one or more of, limiting speed value, set limits and threshold limit values.
9. The speed governing system according to claim 1, wherein the speed governor further comprises a speed sensor interface configured to receive input from at least one of, a vehicle speed senor, a dedicated speed sensor associated with the speed governing system, and a global positioning system module.
10. The speed governing system according to claim 1, wherein the threshold limit value is lesser than the limiting speed value.
11. The speed governing system according to claim 1, wherein the limiting speed value and the threshold limit value can be manually set by a user by connecting to the speed governor.
12. The speed governing system according to claim 1, wherein the processor is further configured to automatically generate the threshold limit value based on the limiting speed value.
13. The speed governing system according to claim 1, wherein the processor is further configured to sense tampering of the instant vehicle speed signal and limit the speed of the vehicle.
14. The speed governing system according to claim 1, wherein the processor is further configured to sense tampering of an input supply voltage and limit the speed of the vehicle.
15. The speed governing system according to claim 1, wherein the speed governor is connected either in series, parallel or partially series to an electronic throttle pedal and an vehicle control unit.
16. A speed governing method to limit speed of a vehicle to a limiting speed value, the method comprising:
receiving one or more independent acceleration request from one or more input channels;
comparing instant speed of the vehicle with at least one of nearest threshold limit value and limiting speed value;
comparing the independent acceleration requests rate of acceleration with a set limit corresponding to the nearest threshold limit value;
modifying independently the one or more independent acceleration request received from one or more input channels based on at least one of the comparisons.
17. A speed governing system to limit the speed of a vehicle to a limiting speed value as herein above described in the specification with reference to figures.
18. A speed governing method to limit the speed of a vehicle to a limiting speed value as herein above described in the specification with reference to figures. ,TagSPECI:F O R M 2
THE PATENTS ACT, 1970
(39 of 1970)
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. TITLE OF THE INVENTION
SPEED GOVERNING SYSTEM AND METHOD

2. APPLICANTS
a. Name: Race Dynamics India Pvt. Ltd.
b. Nationality: India
c. Address: 97/A, Chikyallappa Industrial Estate, Jakkasandra, Koramangala 1st Block, Bangalore – 560034

Complete specification:
The following specification particularly describes the invention and the manner in which it is to be performed.


BACKGROUND
Field
[0001] The disclosed subject matter relates to the field of automobiles, more particularly but not exclusively, to a device for limiting the speed of a vehicle.
Discussion of related field
[0002] Vehicles are widely used for private and public transport. On one hand, latest technological innovations, automobile designs and improved infrastructure are helping the vehicles to realize greater speeds. On the other hand, high speeds are the prime reason for most of the accidents. Vehicles travelling at a greater speed will not be as dynamically stable and controllable when compared to lower speeds. Further, at greater speeds, the engine is made to work harder than it normally would, which results in a reduced lifetime of the engine. Considering these factors, many countries in the recent years have made it mandatory to use speed limiters on public transport vehicles and goods carrying vehicles.
[0003] One conventional technology tried to address this problem by associating a mechanical lead screw with the acceleration paddle to restrict the movement of the acceleration paddle beyond a set limit. Further, the vehicle can be limited to a particular speed by rotating the lead screw. However, this approach is completely mechanical is nature and does not consider the real time speed of the vehicle.
[0004] Another conventional technology tried to address the problem by electronically sensing the acceleration requested from the acceleration pedal through two channels with different characteristics. Further, when the vehicle approaches a predetermined speed limit, output of each of the two channels is modified, such that, the ratio of the outputs before and after modification remains the same. The modified output is communicated to the vehicle control unit, thereby limiting the speed of the vehicle. The vehicle manufacturers include two or more independent channels for throttle position sensing for redundancy and robustness. However, this technology uses a single system to receive request for multiple throttle input channels and limit the speed of the vehicle, thereby, compromises on redundancy. Further, if one of the input channels malfunctions then the speed limiting functionality is adversely affected.
[0005] In light of the forgoing discussion, there is a need for a reliable technique to govern the speed of vehicles.

STATEMENT OF INVENTION
[0006] Accordingly, the invention provides a speed governing system to limit speed of a vehicle to a limiting speed value. The speed governing system includes a speed governor. The speed governor comprises one or more input channels and a processor. The processor is configured to receive one or more independent acceleration request from one or more input channels, compare instant speed of the vehicle with at least one of nearest threshold limit value and limiting speed value, compare the independent acceleration with a set limit corresponding to the nearest threshold limit value, and independently modify the one or more independent acceleration request received from one or more input channels based on at least one of the comparisons.
[0007] There is also a method of speed governing to limit speed of a vehicle to a limiting speed value. The method includes receiving one or more independent acceleration request from one or more input channels, comparing instant speed of the vehicle with at least one of nearest threshold limit value and limiting speed value, comparing the independent acceleration requests rate of acceleration with a set limit corresponding to the nearest threshold limit value, modifying independently the one or more independent acceleration request received from one or more input channels based on at least one of the comparisons.

BRIEF DESCRIPTION OF DRAWINGS
[0008] Embodiments are illustrated by way of example and not limitation in the Figures of the accompanying drawings, in which like references indicate similar elements and in which:
[0009] FIG. 1 illustrates an example block diagram of a speed governing system 1000 configured to limit speed of a vehicle to a predetermined value, in accordance with an embodiment;
[0010] FIG. 2 illustrates an example graph 20 indicating the change in the rate of acceleration after the threshold limit, in accordance with an embodiment;
[0011] FIG. 3 illustrates an example graph 30 comparing the overshoot speed and settling time for a speed governor 200 with controlled rate of acceleration after the threshold limit and a speed governor 200 without a threshold limit, in accordance with an embodiment;
[0012] FIG. 4 illustrates a complete series connection between ETP 100, speed governor 200 and VCU 300, in accordance with an embodiment;
[0013] FIG. 5 illustrates a partial series connection between ETP 100, speed governor 200 and VCU 300, in accordance with an embodiment; and
[0014] FIG. 6 illustrates a complete parallel connection between ETP 100, speed governor 200 and VCU 300, in accordance with an embodiment.

DETAILED DESCRIPTION
[0015] The following detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show illustrations in accordance with example embodiments. These example embodiments are described in enough detail to enable those skilled in the art to practice the present subject matter. However, it will be apparent to one of ordinary skill in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to unnecessarily obscure aspects of the embodiments. The embodiments can be combined, other embodiments can be utilized or structural and logical changes can be made without departing from the scope of the invention. The following detailed description is, therefore, not to be taken as a limiting sense.
[0016] In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one. In this document, the term “or” is used to refer to a nonexclusive “or,” such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated.
[0017] Embodiments disclose techniques to govern the speed of a vehicle equipped.
[0018] FIG. 1 illustrates an example block diagram of a speed governing system 1000 configured to limit speed of a vehicle to a limiting speed value, in accordance with an embodiment. The speed governing system 1000 includes an ETP 100, a speed governor 200 and a Vehicle Control Unit (VCU) 300. The ETP 100 is configured to sense acceleration request by the driver by electrically communicating with the vehicle’s accelerating pedal and forward the sensed request to the speed governor 200. The speed governor 200 is configured to receive one or more independent acceleration request from the ETP 100, through one or more independent input channels of the speed governor 200. The speed governor 200 modifies the received acceleration request if the instant speed of the vehicle is greater than the limiting speed value, or if the received independent acceleration request results in higher rate of acceleration than the set limit of the corresponding nearest threshold limit value. Further, if none of the aforementioned conditions are satisfied then the speed governor 200 forwards the received acceleration request to the VCU 300 without any modifications. The VCU 300 is configured to receive one or more independent acceleration requests from the speed governor 200 and modify operation of one or more vehicle’s parts accordingly.
[0019] In an embodiment, the threshold limit value is lower than the limiting speed value.
[0020] In an embodiment, the set limit is a predetermined rate of acceleration limit corresponding to the threshold limit value.
[0021] In an embodiment, there can be one or more threshold limits with atleast one set limit associated with each of the threshold limit.
[0022] In an embodiment, the ETP 100 can include one or more sensors. Each of the sensors independently sense the acceleration request depending on the operation of a mechanical throttle of the vehicle. Thereafter, the sensed acceleration request is communicated to the speed governor 200 through one or more independent input channels. Further, each of these channels is assigned with an independent ground and voltage supply.
[0023] In an embodiment, the request received by the speed governor 200 from the ETP 100 can either be acceleration request or torque request. It shall be noted that, throughout this document the term torque request can be used as an alternative to the acceleration request. In light of the subject matter disclosed in this document, it should be apparent to a person with ordinary skill in the art that, acceleration request is similar to torque request.
[0024] In an embodiment, the speed governor 200 can include a processor 214, a memory unit 204, an Analog to Digital Convertor (ADC) 202, a communication interface 212, a speed sensor interface 210, an input voltage interface 208 and an output drive module 206.
[0025] In an embodiment, the communication interface 212 enables the speed governor 200 to communicate with one or more external devices. The one or more external devices can modify the operation of the speed governor 200. For example, a user can assign or modify the limiting speed value, threshold limit value and the set limits associated with the threshold limit value, among others parameters, using an authorized device through the communication interface 212.
[0026] In an embodiment, the communication between the speed governor 200 and the one or more authorized external devices is established through a wired medium, wireless medium or a combination of both wired and wireless medium.
[0027] In an embodiment, the speed sensor interface 210 can be connected to one or more of a vehicle speed sensor, a GPS module, accelerometer, RPM meter and gear sensor combination, and a dedicated speed sensor associated with the speed governor 200, among others. Further, the speed sensor interface 210 communicates the instant speed of the vehicle to the processor 214.
[0028] In an embodiment, the speed governor 200 is powered by an external voltage source, such as, a battery, through the input voltage interface 208. The input voltage interface 208 is further configured to regulate and condition the voltage from the external voltage source.
[0029] In an embodiment, ADC 202 is configured to receive one or more independent analog acceleration request from the ETP 100 and convert it into a digital signal and communicate each of the requests independently to the processor 214.
[0030] In an embodiment, the output drive module 206 is configured to communicate the modified independent acceleration request to the VCU 300.
[0031] In an embodiment, the memory unit 204 is configured to store data pertaining to limiting speed value, threshold limit value and set limit, among other types of data.
[0032] In an embodiment, the processor 214 is configured to communicate with all the other modules of the speed governor 200, independently modify the one or more acceleration requests received from one or more independent channels based on the comparisons and communicate the same to the VCU 300.
[0033] In an embodiment, the processor 214 receives one or more independent acceleration request from the ETP 100 through one or more input channels associated with the speed governor 200 for redundancy. Further, the speed governor 200 governs the received one or more independent acceleration request from each of the channels separately and communicates the same separately to the VCU 300.
[0034] In the instant embodiment, the acceleration request signal from the input channel is fed to the ADC 202 of the speed governor 200. The ADC 202 converts the analog acceleration request signal received from the ETP 100 to a digital signal and communicates the converted digital signal to the processor 214. The processor 214 modifies the received acceleration request if the instant speed of the vehicle received from the speed sensor interface 210 is greater than the limiting speed value stored in the memory unit 204, or if the received independent acceleration request results in higher rate of acceleration than the set limit of the corresponding nearest threshold limit value. Further, if none of the aforementioned conditions are satisfied then the processor 214 forwards the received acceleration request to the VCU 300 without any modifications.
[0035] In an embodiment, the memory unit 204 can include one or more threshold limit values and corresponding one or more set limits. Further, when a vehicle reaches a threshold limit value, the processor 214 modifies the received independent acceleration request, if the received acceleration request results in an increased rate of acceleration than the set limit associated with the threshold limit.. Such modification of the acceleration request limits the rate of acceleration, thereby limiting the extent to which the speed of the vehicle overshoots the limiting speed and settling time of the vehicle.
[0036] In an embodiment, the overshoot speed is the maximum speed attained by the vehicle beyond the limiting speed value, despite the actions performed the speed governor 200. The settling time is the time taken by the vehicle to settle at the limiting speed value once the vehicle crosses the limiting speed value.
[0037] FIG. 2 illustrates an example graph 20 indicating the change in the rate of acceleration after a threshold limit, in accordance with an embodiment. In case of a predefined threshold limit value stored in the memory unit 204, when the vehicle reaches the speed equal to the threshold limit value VThreshold, the processor 214 of the speed governor 200 senses it, compares the calculated resulting rate of acceleration with the set limit associated with the threshold limit value and modifies the acceleration request if the resulting rate of acceleration is greater than the set limit. This can be observed in graph 20 where, when the vehicle reaches the threshold limit VThreshold the vehicle speed takes the reduced rate of acceleration path 22 instead of the normal rate of acceleration path 24. The change in rate of acceleration ACR can also be noticed in the graph 20. It shall be noted that, there can be multiple threshold limits and multiple set limits associated with the threshold limit to improve the speed governing system.
[0038] FIG. 3 illustrates an example graph 30 comparing the overshoot speed and settling time for a speed governor 200 with controlled rate of acceleration after the threshold limit and a speed governor 200 without a threshold limit, in accordance with an embodiment. It can be observed from the graph 30 that, when the vehicle reaches the threshold limit value VThreshold, the rate of acceleration decreases and follows the reduced rate of acceleration path 22 deviating from its normal rate of acceleration path 24, thus decreasing the overshoot speed value from VOC to VOT and settling time from TSC to TST.
[0039] In an embodiment, the processor 214 is configured to automatically calculate the threshold limit value and the corresponding set limits based on the predefined speed limiting value.
[0040] In an embodiment, the processor 214 is configured to sense tampering of the signal from the external speed sensor to the speed sensor interface 210 and limit the speed of the vehicle to the minimum value based on the speed limiting value.
[0041] In an embodiment, the processor 214 is configured to sense tempering of the input supply voltage from the input voltage interface 208 and limit the speed of the vehicle to the minimum value based on the speed limiting value by activating the speed governor 200 through the voltage from the ETP 100.
[0042] FIG. 4 illustrates a complete series connection between the ETP 100, speed governor 200 and VCU 300, in accordance with an embodiment. The speed governor 200 is connected in series to both ETP 100 and VCU 300. Further, two or more channels 42 and 44 of the ETP 100 are isolated from each other and are governed separately by the speed governor 200. Thereafter, the governed channels 42 and 44 are fed to the VCU 300 separately, thereby allowing the VCU 300 to efficiently choose one or more of the channels 42 or 44 to operate the vehicle parts.
[0043] FIG. 5 illustrates a partial series connection between the ETP 100, speed governor 200 and VCU 300, in accordance with an embodiment. In this mode of connection, the electronic throttle pedal signal S1 and S2 from each of the channels 42 or 44 is connected in series with the speed governor 200 and the rest of the signals are connected in parallel to the speed governor 200.
[0044] FIG. 6 illustrates a complete parallel connection between ETP 100, speed governor 200 and VCU 300, in accordance with an embodiment. In this mode of connection, the speed governor 200 is connected in parallel to the ETP 100 and the VCU 300.
[0045] In an embodiment, the speed governor 200 can receive inputs from one or more sensors in the vehicle, such as, sensor configured to sense the vibrations in the vehicle and senor associated with the suspension of the vehicle, among others sensors. Further, the speed governor 200 can modify the operation of the vehicle parts based on the received inputs from the sensors and the data stored in the memory unit 204.
[0046] In an embodiment, the speed governor includes an adaptive capability, to take into account changes in magnitude of input acceleration request due to mechanical tolerances or wear and tear due to usage of the accelerator pedal. For example, in a mechanical system with analog output for acceleration request, a minimum request of 0% might relate to 0.3 V on channel 1, but might degrade to 0.28V after a year.
[0047] In an embodiment, the speed governor 200 can include a proportional integrated derivative (PID) or any suitable closed loop controller to modify the acceleration request to the VCU 300. Further, the PID controller can take into account vehicles behavior or characteristics including weight, acceleration, deceleration, power surge, hunting and response time, among others and perform a refined action of speed limiting.
[0048] The speed governor 200 enables channels 42 and 44 to communicate separately with the VCU 300. This type of isolated channel 42 and 44 communication enables the VCU 300 to operate normally even if one of the channels 42 or 44 malfunctions. For example, if the channel 42 malfunctions, the VCU 300 receives the acceleration request from both the channels 42 and 44, and decides to operate according to the signal received from channel 44. Thus, single point failure, which is one of the drawbacks of the conventional technologies is addressed.
[0049] Additionally, while the process described above and illustrated in the drawings is shown as a sequence of steps, this was done solely for the sake of illustration. Accordingly, it is contemplated that some steps may be added, some steps may be omitted, the order of the steps may be re-arranged, and/or some steps may be performed simultaneously.
[0050] The example embodiments described herein may be implemented in an operating environment comprising software installed on a computer, in hardware, or in a combination of software and hardware.
[0051] Although embodiments have been described with reference to specific example embodiments, it will be evident that various modifications and changes may be made to these embodiments without departing from the broader spirit and scope of the system and method described herein. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.
[0052] Many alterations and modifications of the present invention will no doubt become apparent to a person of ordinary skill in the art after having read the foregoing description. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. It is to be understood that the description above contains many specifications, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the personally preferred embodiments of this invention. Thus the scope of the invention should be determined by the appended claims and their legal equivalents rather than by the examples given.

CLAIMS
We claim:
1. A speed governing system to limit speed of a vehicle to a limiting speed value, the speed governing system comprising:
a speed governor, wherein the speed governor comprises:
one or more input channels;
a processor configured to:
receive one or more independent acceleration request from one or more input channels;
compare instant speed of the vehicle with at least one of nearest threshold limit value and limiting speed value;
compare the independent acceleration with a set limit corresponding to the nearest threshold limit value;
independently modify the one or more independent acceleration request received from one or more input channels based on at least one of the comparisons.
2. A speed governing system according to claim 1, wherein the one or more independent acceleration request is modified if the instant speed of the vehicle is greater than the limiting speed value.
3. A speed governing system according to claim 1, wherein the one or more independent acceleration request is modified if the instant speed is greater than nearest threshold limit value, and the requested rate of acceleration is greater than the set limit corresponding to the nearest threshold limit value.
4. A speed governing system according to claim 1, wherein the speed governor includes a plurality of threshold limit values and set limit values.
5. The speed governing system according to claim 1, further comprising an electronic throttle pedal, wherein the electronic throttle pedal comprises
one or more channel and a throttle pedal in the vehicle, wherein, each of the channels are configured to sense the acceleration request from a throttle pedal in the vehicle, with each of the channels having its own characteristics, supply and ground connection.
6. The speed governing system according to claim 1, further comprising a vehicle control unit configured to modify the operation of different parts of the vehicle based on the acceleration request received from the speed governor.
7. The speed governing system according to claim 1, wherein each of the input channels are independently governed by the speed governor.
8. The speed governing system according to claim 1, wherein the speed governor further comprises a memory unit configured to store information corresponding to one or more of, limiting speed value, set limits and threshold limit values.
9. The speed governing system according to claim 1, wherein the speed governor further comprises a speed sensor interface configured to receive input from at least one of, a vehicle speed senor, a dedicated speed sensor associated with the speed governing system, and a global positioning system module.
10. The speed governing system according to claim 1, wherein the threshold limit value is lesser than the limiting speed value.
11. The speed governing system according to claim 1, wherein the limiting speed value and the threshold limit value can be manually set by a user by connecting to the speed governor.
12. The speed governing system according to claim 1, wherein the processor is further configured to automatically generate the threshold limit value based on the limiting speed value.
13. The speed governing system according to claim 1, wherein the processor is further configured to sense tampering of the instant vehicle speed signal and limit the speed of the vehicle.
14. The speed governing system according to claim 1, wherein the processor is further configured to sense tampering of an input supply voltage and limit the speed of the vehicle.
15. The speed governing system according to claim 1, wherein the speed governor is connected either in series, parallel or partially series to an electronic throttle pedal and an vehicle control unit.
16. A speed governing method to limit speed of a vehicle to a limiting speed value, the method comprising:
receiving one or more independent acceleration request from one or more input channels;
comparing instant speed of the vehicle with at least one of nearest threshold limit value and limiting speed value;
comparing the independent acceleration requests rate of acceleration with a set limit corresponding to the nearest threshold limit value;
modifying independently the one or more independent acceleration request received from one or more input channels based on at least one of the comparisons.
17. A speed governing system to limit the speed of a vehicle to a limiting speed value as herein above described in the specification with reference to figures.
18. A speed governing method to limit the speed of a vehicle to a limiting speed value as herein above described in the specification with reference to figures.

ABSTRACT
A speed governing system (1000) to limit speed of a vehicle to a limiting speed value includes a speed governor (200). The speed governor (200) includes one or more input channels and a processor (214) configured to receive one or more independent acceleration request from one or more input channels, compare instant speed of the vehicle with at least one of nearest threshold limit value and limiting speed value, compare the independent acceleration with a set limit corresponding to the nearest threshold limit value, independently modify the one or more independent acceleration request received from one or more input channels based on at least one of the comparisons.
Reference figure: FIG. 1